July 31, 2009

Foliar fertilisation for sugar beets in case of acute nutrient deficiency

During the course of a vegetation period, sugar beet crops may temporarily exhibit acute nutrient deficiencies, specifically relating to micronutrients. One of the causes may be aridity. In such cases of deficiency, foliar fertilisation represents a valuable tool for effective and cost-efficient rectification for such nutrient insufficiencies.

Nutrient deficiency in case of aridity or high pH-value

With their long, deep-reaching roots sugar beets are able to extract water from deeper layers of the soil. However, dry spells may result in a situation in which nutrients from the soil’s top layer are not available to the plant. Micronutrients such as manganese or boron are detained in the soil during dry spells or in case of high pH-values. As a result, the foliar apparatus may exhibit deficiency symptoms.

Sugar beet deficiency symptoms

In case of boron deficiency, sugar beets show fissured, scabby-brown spots on their leaf stalks. Boron deficiency impedes the transport of assimilates in the root’s body, thereby decreasing the sugar yield. The meristem or vegetation cone begins to die off, and the common diseases dry rot or heart rot occur.

Boron deficiency in sugar beets

Manganese deficiency results in chlorotic mottling between leaf veins, thereby reducing the photosynthetically active foliage surface. Boron and manganese deficiencies initially become visible in younger leaves, as both nutrients cannot be translocated from older leaves to younger foliage.

Manganese deficiency in sugar beets

Foliar fertilisation safeguards sugar beet yields

Recent research conducted by the University of Bonn has shown that plants are capable of translocating boron after foliar application – even if not entirely. Foliar fertilisation is therefore suited to correct manganese deficiency in the existing leaf apparatus. However, in case of long-term deficiency, such as during longer dry spells, the measure needs to be repeated in order to provide for new foliage.

Foliar fertilisation with manganese results in regreening of the affected leaf surface, which can then again contribute to yield formation. Foliar fertilisation with boron, however, prevents further damage to the vessels and therefore an even more pronounced reduction of the sugar yield. It is therefore absolutely necessary to apply these nutrients in a timely manner, i.e. at the beginning of a longer period of drought, respectively before symptoms have already appeared.

Fertilisation recommendation

EPSO Microtop is an excellent source of these micronutrients. Repeated application of EPSO Microtop from row closure onwards, in combination with fungicide application, will safeguard sugar yields.